On Tue, 3 Sep 2013 23:50:09 +0200
Eduardo Morras emorr...@yahoo.es wrote:
Don't know if column collation overrides index collation or viceversa.
It's probably simpler to think of them as two things, table and index.
Neither overrides the other.
Ideally, they use the same collation. In the
1. If you define a column with NOCASE and later an index without, it
won't be possible to insert two values differing only by case,
because the column will reject it.
Of course it will accept the value, unless you declared the column unique so
that a unique index is created using the nocase
On Mon, 2 Sep 2013 13:48:02 +0100
Simon Slavin slav...@bigfraud.org wrote:
On 2 Sep 2013, at 8:25am, Eduardo Morras emorr...@yahoo.es wrote:
Or create the index with collate
CREATE INDEX idx_collated_column ON myTable ( column COLLATE NOCASE )
The problem with doing it in the index
On Mon, 2 Sep 2013 02:12:05 +0100
Simon Slavin slav...@bigfraud.org wrote:
On 2 Sep 2013, at 2:03am, Joseph L. Casale jcas...@activenetwerx.com wrote:
I am using LIKE as the columns are indexed NOCASE and I need the
comparison case insensitive.
Have you tried using '=' ?
Also if
On 2 Sep 2013, at 8:25am, Eduardo Morras emorr...@yahoo.es wrote:
Or create the index with collate
CREATE INDEX idx_collated_column ON myTable ( column COLLATE NOCASE )
The problem with doing it in the index is that it's hard to predict when SQLite
will use a particular index. Better to
: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-
boun...@sqlite.org] On Behalf Of Simon Slavin
Sent: Monday, 2 September, 2013 06:48
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Query problems
On 2 Sep 2013, at 8:25am, Eduardo Morras emorr...@yahoo.es wrote
Plus, of course, index will only ever be used for operations where you have
overridden the default collating sequence for the operation, for example by
specifying collate nocase in the join expression, or adding the collate
nocase to
the order by or group by.
I assume this explains why the
I have a query that is unbearable at scale, for example when
s_table_a and s_table_b have 70k and 1.25M rows.
SELECT s.id AS s_id
,s.lid AS s_lid
,sa.val AS s_sid
,d.id AS d_id
,d.lid AS d_lid
FROM s_table_b sa
JOIN d_table_b da ON
(
da.key=sa.key
Hi,
Can you do DESCRIBE QUERY PLAN your_query and post results here?
Also, what do you mean by unbearable at scale? Did you measure it? What
is the result?
Thank you.
On Sun, Sep 1, 2013 at 6:03 PM, Joseph L. Casale
jcas...@activenetwerx.comwrote:
I have a query that is unbearable at scale,
On 2 Sep 2013, at 2:03am, Joseph L. Casale jcas...@activenetwerx.com wrote:
I am using LIKE as the columns are indexed NOCASE and I need the
comparison case insensitive.
Have you tried using '=' ?
Also if you declare the columns as COLLATE NOCASE in your table definition,
then using '='
Hi,
Can you do DESCRIBE QUERY PLAN your_query and post results here?
Also, what do you mean by unbearable at scale? Did you measure it? What
is the result?
Thank you.
It doesn't finish with maybe 4 or 5 hours run time.
Sorry, do you mean explain query plan ...?
0 0 1
Have you tried using '=' ?
Also if you declare the columns as COLLATE NOCASE in your table definition,
then using '=' will definitely work the way you want it to. An example would
be
CREATE TABLE myTable (myName TEXT COLLATE NOCASE)
Simon.
I did and it excluded the comparisons whose
I am using LIKE as the columns are indexed NOCASE and I need the
comparison case insensitive. I suspect this is where is breaks down
but I don't know enough sql to really appreciate the ways I could
approach this better.
LIKE is used when comparing strings with wildcards. For example, val
Hi, Joseph,
On Sun, Sep 1, 2013 at 6:21 PM, Joseph L. Casale
jcas...@activenetwerx.comwrote:
Hi,
Can you do DESCRIBE QUERY PLAN your_query and post results here?
Also, what do you mean by unbearable at scale? Did you measure it? What
is the result?
Thank you.
It doesn't finish
LIKE is used when comparing strings with wildcards. For example, val LIKE
'abra%' (which will match 'abraCaDAbra' and 'abrakadee'.
If there are no wildcards you should be using =, not LIKE. LIKE will/should
always indicate that a table or index scan is required, perhaps of the whole
0 0 1 SCAN TABLE d_table_b AS da (~10 rows)
Is this the index you referenced in you reply to Simon?
Maybe you are using wrong index/column?
I'll recheck, I am also reading up on indexes as they relate to optimizing
queries. Could be I made a mistake.
I had the same
Have you tried using '=' ?
Also if you declare the columns as COLLATE NOCASE in your table definition,
then using '=' will definitely work the way you want it to. An example would
be
CREATE TABLE myTable (myName TEXT COLLATE NOCASE)
Simon,
That took this query from not finishing in 5
The below statement returns records:
SELECT * FROM recordings WHERE key LIKE
'4df0247ce1a97685a782d2cb051b48ed952e666c';
But this one does not:
SELECT * FROM recordings WHERE key =
'4df0247ce1a97685a782d2cb051b48ed952e666c';
The only difference is that = and LIKE have been swapped.
I realize
If the value in key is a blob, then like matches it and = does not.
Because like has to do a string conversion on key, it also doesn't use
the index.
Try:
SELECT * FROM recordings WHERE key =
cast('4df0247ce1a97685a782d2cb051b48ed952e666c' as blob);
Or try inserting the key as text in the
On Thu, Sep 29, 2011 at 08:32:04PM -0400, Eric Anderson scratched on the wall:
The below statement returns records:
SELECT * FROM recordings WHERE key LIKE
'4df0247ce1a97685a782d2cb051b48ed952e666c';
But this one does not:
SELECT * FROM recordings WHERE key =
On Thu, Sep 29, 2011 at 8:42 PM, David Garfield
garfi...@irving.iisd.sra.com wrote:
If the value in key is a blob, then like matches it and = does not.
Thanks. This suggestion helped me track down the issue. I was actually
going through ActiveRecord (the ORM for Ruby on Rails). Was upgrading
my
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